1. Field of the Invention
This invention relates to the field of high-speed watercraft and more specifically to a hydrofoil watercraft with a V-shaped adjustable hydrofoil and ground-effect mode.
2. Discussion of Prior Art
Originally, hydrofoil watercraft consisted of a conventional boat design with a hydrofoil wing attached. These early designs failed to overcome the speed limitation of a foil-in-water due to high drag and cavitation as the foil reached certain speeds. They were vulnerable to floating debris, especially as speeds increased, posing a serious safety risk for occupants. In addition, the hull was not aerodynamically efficient further limiting high-speed operation. Later designs attempted to streamline the hull and incorporated overly complex retractable designs. One design is U.S. Pat. No. 4,080,922 to Brubaker. The Brubaker patent uses complex rotatable foil elements that provide minimal lift when partially deployed at low speeds or in shallow water. Maximum lift is only available when fully extended, which hinders shallow water low speed transition to hydrofoil operation. Brubaker also uses a bow foil arrangement that provides a stepped lift due to multiple foil segments. This would result in erratic lift and control. Brubaker's cabin design with a downward sloping nose would pose serious washover problems when in displacement mode (called hullborne by Brubaker). Another design is U.S. Pat. No. 3,762,355 to Raynes. The Raynes patent uses a float plane design requiring wider wing span and thus limit dockside flexibility as well as the ground-effect advantage. Still other designs use submerged propellers for propulsion at low speeds limiting shallow water operation and increasing weight and complexity.